Process for forming yarns from certain woven or knit textiles



July 8, 1969 M. RADOFF 3,453,816

' PROCESS FOR; FORMING YARNS FROM CERTAIN WOVEN OR KNIT TEXTILES Filed June 8. 1966 Z .1 all M Q77A/ Rana/ F INVEN'TOR.

United States Patent 3,453,816 PROCESS FOR FORMING YARNS FROM CERTAIN WOVEN OR KNIT TEXTILES Martin Radoif, 5943 Ostrom, Encino, Calif. 91316 Filed June 8, 1966, Ser. No. 556,225 Int. Cl. D02g 3/06, 3/08; D01h 11/00 US. Cl. 57-155 9 Claims ABSTRACT OF THE DISCLOSURE A process for forming yarn from a woven or knit textile containing thermoplastic fibers by subjecting an elongated relatively narrow strip of the textile to tensional force exerted lengthwise thereof and simultaneously softening its fibers, thereby permitting its edges to curl inwardly to form a generally tubular filament, and then hardening the fibers to retain that form.

This invention relates to the manufacture of a new and novel type of yarn or yarn-like product, and more particularly to a process for forming such a product from certain textiles containing thermoplastic fibers.

In the textile industry yarn is generally defined as the continuous strand formed by twisting spun fibers on a spinning frame. The fibers from which the yarn is formed may be animal, vegetable, mineral or synthetic, or a combination of these, and by the proper selection of fibers and spinning techniques a limited number of finishes and textures may be obtained in the yarn finally produced. Single or multiple strands of yarn may be used for weaving, knitting or chrocheting textiles having an even wider variety of finishes, textures, surface effects, and physical characteristics, such as stretchability, heat conductivity or reflectivity, irridescence, and the like. When several yarns are twisted together to produce strong strands for sewing purposes, the product is known as thread.

It will thus be seen that in the present practice the starting material in the formation of yarn is the spun fiber. In the subject invention, on the other hand, the starting material in the production process is a textile, which has previously been woven or knitted from such yarn.

The textile industry and the many users it supplies with fabrics, cloths and materials for a plethora of uses are continuously searching for new materials and methods to provide the broadest range of finishes, textures, surface elfects and physical characteristics. Tangible evidence of this quest may be found in the fact that the list of commonly known descriptive terms, trademarks and trade names of textiles presently available on the commercial markets extends to in excess of nine hundred. The need for additions to this list is a continuing and widely recognized one.

It has long been known that when certain resilient materials in sheet form are subjected to opposed external tensional forces, unbalanced internal forces are set up which tend to cause their lateral edges to curl inwardly. This phenomenon has been noted particularly in connection with continuous sheeting made of plastics, rubber hydrochlorides, certain vinylidene chloride copolymer latexes and the like. Some limited use has been made of this characteristic in processes for preparing thermoplastic tapes of varied cross-sections and thread-like structures from specific starting materials. Invariably these processes have been applied only to starting materials in the form of sheets, sheeting, webs, ribbons, films, foils, rods, filaments, and threads, many of which must be specially prepared in order to serve their intended purpose. The products resulting from these techniques, while changed in cross-sectional form from planar sheets to generally tubular filaments or overlapping tapes, are of little more value to the textile industry and its customers than solid filaments produced from their raw starting materials.

It has been observed that certain woven and knit textiles exhibit a tendency to curl inwardly at their edges under theinfluence of longitudinally applied opposed tensional forces similar to that exhibited by the continuous sheets described in the prior art literature. Extensive investigation has demonstrated that by preparing these textiles in elongated strips of appropriate widths, subjecting the strips to simultaneous longitudinal stretching under opposed tensional forces and the application of heat, and then allowing them to cool or cooling them, they form permanently rolled tubular elements having all of the characteristics of the original textiles from which they are produced. These elements, while not the product of spinning, and therefore not true yarns as that term is customarily used, have all of the attributes of such yarn and may be used to serve all of the purposes served by conventional yarn, and indeed additional purposes to which classical yarn does not readily lend itself.

It is an object of the subject invention, therefore, to provide a process whereby yarn of a new and novel character is formed from certain types of woven or knit textiles.

Despite the fact that considerable experimentation has been performed in an attempt to define the physical theory which makes the process of the subject invention operative in the case of certain textiles but not others, no completely acceptable explanation has been discerned. It is clear that internal forces are created within the textile itself, which tend to pull or force the lateral edges inwardly; however, no single general theory has satisfactorily explained the exact nature of these forces, their formation, or their accurate predictability. And no universally supportable answer has been given to the question why certain textiles, even when they exhibit the curling tendency described earlier, are permanently deformed under the influence of the heat when others having very similar if not identical physical characteristics, at least to all superficial appearances, are not permanently affected by the application of either tension or heat, or both. It is hypothesized, and it must be home in mind that this is onl an hypothesis, and is subject to possible critism or rejection, based upon further experimentation, that when incorporated in certain types of weaves or knits, such as tricots, jerseys, double knits and others, thermoplastic fibers, that is fibers which exhibit a softening without attendant physical or chemical deterioration, at least at moderate temperatures, contribute in some presently unknown cooperative manner to the formation of relatively uniform internal forces which cause the observed results.

It is, therefore, another object of this invention to provide a process for controlling the unbalanced internal forces created within a textile containing thermoplastic fibers in order to convert relatively narrow elongated strips of such textiles into tubular elements which may be used in place of conventional yarns.

A further purpose is to provide a process for applying optimum tensional forces longitudinally of such a strip of textile and subjecting the strip to the proper degree of heat, thereby causing its edges to curl inwardly to form a generally tubular element, and thereafter permitting the tubular element thus formed to cool and thus permanently retain its newly acquired configuration.

Still another object is to provide an apparatus whereby the process of the subject invention may be practiced on a commercial manufacturing scale.

Yet another object is the provision of a process and equipment for the practice thereof which will permit the formation of an entirely new class of yarns having unique finishes, textures, surface effects, and physical characteristics.

Other objects will become apparent as the invention becomes better understood through the reading of the following description, taken in connection with the appended drawings in which:

FIGURE 1 is a highly simplified side eleva'tional view of an apparatus for practicing the subject invention;

FIGURE 2 is a top view looking downward on the apparatus illustrated in FIGURE 1 with portions thereof cut away for purposes of clarity;

FIGURE 3 is a series of cross-sectional views of the textile strips utilized in the subject invention, taken at positions marked 31;, 3b, 3c and 3d of FIGURE 1;

FIGURE 4 is a top view illustrating another embodiment of the apparatus illustrated in FIGURE 1; and

FIGURE 5 is a partial side elevational view of the apparatus illustrated in FIGURE 4 showing the arrangement of the cutters in that figure.

Referring now to FIGURE 1, the textile selected to be used in the process of the subject invention is prepared in the form of a relatively narrow strip 11, which is mounted on stock drum 12. Drum 12 is adapted to revolve about axle 13 and dispense the strip of textile 11 through a set of retarding rollers, illustrated here by rollers 14 and 15. A set of driven rollers shown here for simplicity purposes as a pair of opposed rollers 16 and 17, draw the strip 11 from drum 12 and through rollers 14 and 15, and takeup drum 23, mounted for driven rotation about axle 24 serves to recover the strip 11 at the end of the process and store it for further use.

Heating means, such as steam chamber 18, are positioned at a point intermediate retarding rollers 14 and 15 and driven rollers 16 and 17. Steam intake 19 permits live steam to be admitted into chamber 18, and liquid outlet 21 enables the condensate formed in the bottom of chamber 18 to be withdrawn. Although not necessary for the practice of the invention, an air blower (not shown) is preferably provided, having outlets 22 intermediate the steam chamber 18 and driven rollers 16 and 17.

The function of the driven rollers 16 and 17 is to apply traction to strip 11, and they may take a variety of forms. In the simplest of these forms roller 17 is mounted for free rotation about a stationary axle while roller 16 is adapted to be driven by conventional means while it is urged toward roller 17. The surface of roller 16 may be prepared to offer sufficient frictional contact with strip 11 to provide the necessary tractional force.

Retarding rollers 14 and 15 may likewise take a variety of forms as, for example, one in which roller 15 is permitted to revolve freely about a stationary axle while roller 14 is urged downwardly toward it at the same time it is braked by conventional means. As with roller 16, roller 14 may be provided with a surface adapted to engage the upper surface of strip 11 in frictional contact, thereby permitting braked roller 14 to retard the movement of the strip 11 toward rollers 16 and 17 By means of such an arrangement strip 11 may be subjected to any desired degree of tensional force along its ma or axis.

FIGURE 2 further illustrates the apparatus shown in FIGURE 1 and, having a portion of the top of chamber 18 cut away, allows a clear view of the effect of the heat contained in the steam in chamber 18 on strip 11.

FIGURE 3 shows in series of greatly enlarged crosssectional views the appearance of strip 11 as it passes through the apparatus of FIGURES 1 and 2. At position a the textile strip 11 is flat and relatively unalfected by the small amount of tensional force needed to pull it from stock drum 12. As it passes through retarding rollers 14 and 15 and is subjected to considerably greater tension, the strip begins to curl as shown at position b. Under the infiuence of still greater tension and the heat imparted by the steam in chamber 18 the strip has completely curled to form a roughly tubular element as shown at position 0. Once cooled by air from blower outlets 22 the strip retains this tubular configuration, however, as it passes between driven rollers 16 and 17 it is flattened somewhat, as shown at position d. This flattened condition persists as the strip is rolled about take-up drum 23; but this flattening is only temporary, and the strip 11 returns the tubular cross-sectional shape shown at position c as soon as it is unwound from take-up drum 23.

For large-scale commercial manufacturing it may be preferable to employ an apparatus such as that illustrated in FIGURES 4 and 5. The chief difference between the device illustrated in FIGURES 4 and 5 and that depicted in FIGURES 1 and 2 lies in the provision of a much wider stock drum 31, on which textiles 32 may be wound for feeding into a series of parallel cutters 33 which cut it into strips 34 of the desired width. These strips are then passed through retarding rollers 35 and 36, steam chamber 37, blower outlets 38, and a pair of driven rollers of which only the upper one (shown at numeral 39) is illustrated. A take-up drum 41 is provided, as in the earlier described device for the receipt and storage of the processed strips 34.

For commercial purposes it may be desirable to furnish yarn in lengths greater than those in which textiles are presently available. For this purpose conventional methods may be used to join the ends of several strips of textile at some stage of the process. This may be done by knotting, sewing, cementing, or any other means. On the other hand, it may be highly desirable to manufacture the textile in greater lengths than are presently available, for the specific purpose of using them in the subject process. Such specially prepared materials could be conveniently made in the desired strip widths, so that further cutting and trimming would not be necessary.

Although as stated earlier the precise reason for the effectiveness of the subject invention is not clearly understood, a number of generalizations can be made from experimental data and observations. It has been noted, for example, that although no special processing of the textile to be utilized in the process is required, the effectiveness of the process is substantially diminished when the textile used has previously been starched. Accordingly, it is highly desirable, if not necessary, to use unstarched materials or to remove the starch from previously treated materials prior to subjecting them to tension and heat in the formation of yarn.

It is of considerable importance to note that the process is equally effective regardless of whether the strip of textile is cut with the length of the original material, with the width of the material, or on the bias. And there is no particular requirement for treatment of the edge of the material after it has been cut. Thus strips having both smooth and relatively ragged edges have been used in producing usable quantities of production quality yarn. From the standpoint of efiicient handling during the manufacturing process it is desirable that the edges of the strips be relatively smooth and straight.

As a practical matter it is simpler to subject the textile strip being processed to tension prior to heating it; but there appears to be no reason why the process cannot be carried out by heating the textile first and then placing it under tension, or by accomplishing both the heating and the stretching simultaneously. In practice, utilizing the apparatus described in the accompanying drawings, the heating and stretching are substantially simultaneous.

The experimental results achieved by using thermoset materials tends to support the hypothesis that the process is related in some manner to the thermoplasticity of the fibers of the textile used. Thermoset fabrics are prepared by autoclaving yarn at a temperature of 250 to 260 Fahrenheit and then quick cooling the yarn to substantially destroy its elasticity. Thermoset textiles containing nylon and other synthetic fibers were either unaffected by the subject process or were affected to such a greatly lessened degree as to be relatively unusable for the commercial manufacture of yarn.

On the other hand, a number of textiles in the form of laminates incorporating a layer of sheet rubber were sub jected to the process of the invention and were found to form a satisfactorily curled yarn, but with an unacceptable deterioration of the rubber layer resulting from the heat applied to the strip. Obviously, where it is desired to apply the subject process to rubber-containing laminates or textiles containing materials which are adversely affected by heat, some alternative method for permanently retaining the curl of the yarn must be used. Such alternative methods are within the scope of the invention.

To this end it has been found that the results sought can readily be achieved by substituting chemical means for heating means to soften and subsequently harden the thermoplastic fibers in stretchable textiles. Thus, by replacing the steam chamber 18 in the apparatus as described in the accompanying drawings with a series of chemical baths chosen first to soften and then re-harden the fibers in the textile strips 11 and 34 and eliminating blower outlets 22 and 38, the end result is substantially identical with that achieved by heating and cooling the strips.

In the initial stages of testing of this process only textiles containing man-made fibers were utilized, and their success led to the conclusion that any thermoplastic fibercontaining material would lend itself to the process. Subsequently, however, experimentation revealed that certain natural materials were usable. As will be seen from the examples which follow, a limited number of fabrics containing wool, cotton and silk were successfully employed. The only conclusion that can be drawn from this evidence at this time is that in the selected weights and weaves or knits the fibers of these materials exhibited a degree of thermoplasticity suflicient to cause the curling noted.

The tubular yarn formed by the subject process is a more or less permanent one, lasting through repeated washings and dry cleanings, as long as the yarn is not subjected to elevated temperatures. The 'permanance is substantially increased when the yarn is knit or woven into new fabrics.

With several exceptions noted below it has been found that the tightness with which the strip of textile may be curled varies inversely with the thickness of knit textiles. Thus the thinnest knits lend themselves readily to the formation of tubular yarns of very small diameters. The strips of such textiles used in the subject process may thus be quite narrow. Less direct consistency is found in the reaction of woven textiles to the process, although by and large the thinner woven materials tend to form more tightly curled yarns. Materials containing synthetic fibers are notable exceptions to this general proposition; however, even within their number the relationship between the thickness of the material and the diameter of the yarn formed is not readily predictable. Of the woven materials used experimentally, only silk has been found to follow the general rule with any degree of uniformity.

Certain classes of knit materials have been found to be totally unusable in this process. Interlock fabrics are the chief among these, exhibiting no tendency to form a permanently curled yarn. So-callecl double knit fabrics containing synthetic fibers are amenable to the process. With these fabrics, the heavier the material and tighter the knit, the thicker the resulting yarn. Such materials may be of particular value when used to knit or weave very bulky fabrics. Interestingly it has been observed that certain double knit Wools are also subject to the process of this invention. Likewise, woolen jersey textiles have been found to work almost as well as textiles containing synthetic fibers.

For illustrative purposes only, and not by way of limitation upon the generality of the subject invention, the following examples are offered to show the specific materials and conditions with which the invention has been practlced.

Example I A variety of tricot and jersey textile samples containmg Nylon yarn in from 15 to 75 denier gauge and marketed commercially under their manufacturers trade names or marks were obtained and cut by hand into strips varying in width from to 1 inch. Sample strips of each of these materials were subjected to longitudinal tensions, up to the limits of their tensile strengths, and from about 1 ounce to about 3% pounds, and simultaneously passed through an atmosphere of live steam at about 212 to 225 Fahrenheit for periods ranging from about 1 second to about /2 minute. The strips were then allowed to cool normally to room temperature (about 75 Fahrenheit). The resulting products were classified generally in four categories, according to whether they formed a permanently curled tubular yarn or not and, if they did, according to whether the yarn was tightly, moderately, or loosely curled.

Each of the sample strips exhibited marked curling and formed what was deemed to be commercially usable yarn. The degree of curling was found to be directly proportional to the fineness of the textile sample (inversely proportional to the denier).

The texture and surface characteristics of the textile had very little, if any, effect on the tightness of the curl, except in the case of those materials having an extremely bulky or wooley appearance, in which instances their very bulk physically prevented them from being tightly compacted in their yarn form.

Within the range employed, the temperature and duration of exposure to heat appeared to have little effect on the characteristics of the yarn produced, at least insofar as the degree of curling was concerned.

The amount of extensive force required for each of the samples varied with the width of the strip used and the fineness of the material itself. The finer the gauge of the fabric, the greater the degree of curling resulting from a given tensile force, the smaller the diameter of the yarn formed from a strip of given width and, conversely, the greater the diameter of yarn capable of being produced under a given tension.

Example 11 The procedure of Example I was followed with commonly available textiles containing rayons, acetates, polyesters, triacetates, acrylics (including specifically Orlon) in both tricot and jersey knits of from 15 to 75 denier and cut into strips of from A to 1 inch. The results in all cases were substantially identical with those observed in Example I.

It was observed that velours and brushed tricots containing the synthetic fibers exhibited the relatively insignificant physical limitation in tightness of .curling referred to in Example I.

Example 111 The procedure of Example I was followed employing strips of textiles containing random combinations of the synthetic fibers tested in Examples I and II, with the same results.

Example IV Random samples of commercially available textiles knit with an interlock stitch and containing synthetic fibers were subjected to the procedure of Example I with no observable result in any case.

Example V Random samples of textiles containing synthetic fibers in the double knit form were subjected to the procedure of Example I with varying results. Substantially all of the materials used exhibited some degree of curling, and most curled sufficiently to form usable yarn. It was ob- 7 served, as might be anticipiated, that the heavier the fabric and tighter the knit, the thicker the resulting yarn and the greater the amount of tension required in the process. By and large the double knit materials do not readily lend themselves to the formation of as wide a variety of yarns as, say, the synthetic tricots and jerseys.

Example VI The procedure of Example I was carried out using strips of substantially pure woolen double knit fabrics, and was found to produce commercially usable yarn in most cases. As with the results of the use of double knit materials containing synthetic fibers, it is believed that the construction of these materials prevents all but the finer of them from being of commercial utility in the form of yarn produced by the subject invention.

Example VII The process of Example I was applied to wool jerseys ranging in weight from 6 ounces to 14 ounces for 58 to 60 inch wide bolts. Commercially acceptable yarns were formed in each case in strips ranging from about A inch to about 1 inch.

Example VIII A variety of woven materials were cut into strips and subjected to the process of Example I with mixed results. Woven textiles containing substantial proportions of one or more of the synthetics, Nylon, rayons, acetates, polyesters, triacetates, and acrylics, demonstrated satisfactory yarn formation, even in the heaviest weights (6 /27 ounces) and highest gauge (125 denier). The nature of the woven synthetic materials was such that the yarns formed were very much thicker in diameter than those formed from any of the knit fabrics utilized in the earlier examples. It was observed, however, that for unexplained reasons in the woven form the materials used exhibited yarn forming characteristics substantially directly opposite to those exhibited by their knit counterparts containing the same fibrous materials. Thus, whereas the lighter the knit fabric the tighter the curling, with the woven textiles, the lighter the weight and the lower the gauge, the less urling results from a given amount of tension. This of course is true only within certain limits for each woven textile, since there is a point for each beyond which the sheer mass of the material itself prevents sufficient curling to permit the formation of a usable yarn.

Within these limits, however, it is possible to create yarns of rather impressive dimensions for special uses.

Sample strips of Woven raw silk subjected to the same process were observed to form very fine yarns of excellent quality, even when cut into strips as narrow as A1 inch. With samples as narrow as this, the amount of tension which could be used was so slight as to be incapable of convenient measurement. Apparently the tensile strength of these strips themselves, rather than the amount of tension required to form the necessary degree of curling to bring the opposite edges of the strip into overlapping positions, is the significant criterion.

Example IX Strips of representative textiles containing all of the synthetic fibers utilized in the prior examples were subjected to heat from a variety of heating sources other than steam, at temperatures ranging from about 200 to about 350. With the exception of those materials in which the fibers deteriorated or the texture surface effects or physical characteristics were physically altered, the results were substantially identical with those achieved in the previous examples. It was found, however, that the optimum temperature range for processing most textiles is from about 210 to about 225.

8 Example X The process of Example I was applied to random samples of both woven and knit textiles containing the synthetic fibers referred to in the earlier examples, prepared in widths ranging from 1 inch to 4 /2 inches, and utilizing sufficient tensile force longitudinally of the strips to effect the maximum degree of curling possible with each particular sample. It was observed that the simultaneous application of extensive force and heat caused the strips to curl to varying degrees, the amount of curling seemingly bearing no particular relationship to the specific fiber composition of the samples.

Of the several knit samples used, none having a Width greater than 1 inch exhibited sufficient curling ability to form a closed tubular element, and the amount of curling varied inversely with the weight of the textile used and inversely with gauge thereof.

In the case of the Woven exemplars, substantially the same results were observed. In one test a 1 /2 inch strip of woven nylon 250 pound test parachute fabric of approximately denier gauge was subjected to the process and exhibited substantial curling, but insutficient to form the desired closed tube.

The foregoing description and examples have been given for the purpose of better enabling the reader to understand the invention itself and its advantages. The invention is not to be construed as limited to the particular forms disclosed herein, but to cover all changes and modifications from this illustrative disclosure.

What is claimed is:

1. A process for forming yarn from a woven or knit textile containing thermoplastic fibers comprising:

preparing an elongated strip of said textile;

subjecting said strip to a tensional force exerted lengthwise thereof;

simultaneously softening said fibers;

permitting the edges of said strip to curl inwardly,

thereby forming a generally tubular filament; and hardening said fibers, thereby retaining the tubular form of said filament.

2. The process for forming yarn described in claim 1 in which said fibers are softened by heating said strip, and are hardened by cooling said tubular filament.

3. The process for forming yarn described in claim 1 in which said fibers are softened by heating said strip to a temperature at least equal to that at which said fibers become softened, but below that at which they become fused, and said fibers are hardened by cooling said tubular filament to a temperature below that at which said fibers become softened.

4. The process for forming yarn described in claim 1 in which:

said tensional force is exerted continuously by passing said strip through spaced movement retarding means and movement inducing means; and

said fibers are softened by heating said strip to a temperature at least equal to that at which they become softened, but below that at which they become fused, and said fibers are hardened by cooling said tubular filament to a temperature below that at which said fibers become softened.

5. The process for forming yarn described in claim 1 in which:

said tensional force is exerted by passing said strip through a set of braked rollers and a set of driven rollers spaced from said braked rollers; and

said fibers are softened by heating said strip to a temperature at least equal to that at which they become softened, but below that at which they become fused, and said fibers are hardened by cooling said tubular filament to a temperature below that at which said fibers become softened.

6. The process for forming yarn described in claim 9 1 in which said strip has a width at least equal to the external circumference of said yarn.

7. The process for forming yarn described in claim 1in which:

said fibers are selected from the group consisting of acrylics, polyesters, rayons, triacetates and nylons; said strip has a width equal at least to the external circumference of said yarn; and said tensional force is exerted by passing said strip through a set of driven rollers spaced from said braked rollers; and

said fibers are softened by passing said strip through an atmosphere of live steam in a region intermediate said movement retarding means and movement inducing means, and are hardened by allowing said tubular filament to cool to a temperature below that at which said fibers become softened.

8. The process for forming yarn described in claim 1 in which said thermoplastic fibers are selected from the group consisting of acrylics, polyesters, rayons, triacetates, and nylons.

References Cited UNITED STATES PATENTS 2,363,457 11/1944 Alderfer 57-167 XR 2,596,246 5/1952 Johnson et al 139-1 XR 2,918,784 12/1959 Faircloth 57-167 3,336,645 8/1967 Mirsky 139-11 XR 3,357,172 12/1967 Evans 57-167 XR JORDAN FRANKLIN, Primary Examiner. W. H. SCHROEDER, Assistant Examiner.

US. Cl. X.R. 57-31, 157, 167; 66-202; 161178 

